Switch locator



Jan. 6, 1953 R. K. SHEWMON 2,524,314

SWITCH LOCATOR Filed May 2, 1951 2 SHEETSSHEET l fijt 17/5 ATTO/Q/VEYSPatented Jan. 6, 1953 SWITCH LOCATOR Ralph K. Shewmon, Dayton, Ohio,assignor to General 'Motors Corporation, Detroit, Mich., a

corporation of Delaware Application May 2, 1951, Serial No. 224,158

8 Claims.

This invention-relates to improvements in centrifugally actuatedswitches and particularly of the type used in electric motors.

The centrifugal switch to which this invention is applied is disclosedin the U. S. Patent 2,182,977 issued to Calvin J. Werner, December 12,1939, which shows the centrifugal switch controlling member carried by arod rigidly secured to the shaft of the rotor of the motor, the switchitself being supported by the end frame of the motor. Such constructionnecessitates precise relative location between the rotor axially and theend frame, for if the centrifugal switch controlling'member and theswitch are not properly spaced, proper operation of the switch will notbe obtained.

The present invention has for one of its objects the provision of anaxially adjustable connection between the driving shaft and thecentrifugal member which permits varying axial positions of the driveshaft relatively to the centrifugal tively to the control device it isintended to operate.

member without disturbing the proper position of said centrifugal memberrela- A further object of the present invention is description,reference being had to the accompanying drawings wherein a preferredembodiment of the present invention is clearly shown.

In the drawings:

Fig. l is a part sectional view of an electric motor equipped with thepresent invention.

Fig. 2 is a fragmentary sectional view taken along the line and in thedirection of the arrows 2-2 in Fig. 1.

Fig. 3 is a fragmentary, sectional view showinga modified form of theinvention.

Fig. 4 is a detail sectional view taken along the line andin thedirection of the arrows 4-4 in Fig. 3 and Fig. 5 is another fragmentary,sectional view illustrating another modified constructionembodyingctheinvention. 1

housing. A rotor 24 is positioned within the stator 23, said rotor beingsupported by a shaft 25 journaled in any suitable supporting membercarried by the end cover 2|.

The end cover 22 provides a platform upon which the switch mechanism forcontrol of the motor is rigidly mounted. This switch mechanism consistsof an insulating plate 30 secured to the platform of the end cover 22 bystuds. 31 and 32, this insulating plate carrying the.

stationary switch terminals 33 and 34. Studs SI and 32 not only securetheinsulating plate 30 to the platform of the end cover 22, but theyalso provide means loosely supporting the movable contact carryingmember 35 of the switch. The numeral 33 in Fig. 1 designates one of apair of stationary terminals secured in alignment on the plate 30.Likewise, the numeral 34 designates one of a pair of stationaryterminals secured in alignment on the insulating plate 30. Movablemember 35 of the switch carries two contacts 36 which are adapted tocooperate with and engage terminals 33 when the movable member of theswitch is in one position, contacts 31 on said movable member beingarranged thereon to cooperate and engage the stationary terminals 34 ofthe switch when said movable member is in the other of its operativepositions. Terminals 33 are electrically connected with the runningwinding of the motor and terminals 34 are connected with the'startingwinding of the motor, all electrical connections being of the usual typeso that when the switch is in the position as shown in Fig. 1, bothstarting and running windings of the electric motor will be operative tostart the motor, the switch being operated by the centrifugal memberwhen'the speed of the motor reaches a predetermined value to disconnectthestarting winding of the motor and render only the tionary terminal32, whereby said movable switch member is loosely supported by theseterminal posts or studs 3| and 32. Stud 3| has a head 45 providing anabutment for the spring 46, the other end of the spring engaging theinsulating collar 40 secured to the movable member of the switch 35.Stud 32 also has an enlarged head portion which acts as a stop againstwhich the insulating collar 4| on the movable member of the switch mayabut. Spring 46 exerts a yieldable force against the one end of themovable member 35 of the switch urging it away from the head portion 45of stud 3| and toward the insulating plate 30. This spring effort thusurges the movable member 35 of the switch, with contact 31 on terminal34 first acting as a pivot, clockwise as regards Fig. l, and later thecontact 36 on said movable member engaging terminal 33 acts as the pivotabout which this clockwise movement of the movable contact member 35under the effect of spring 45 continues. Under thesecircumstancescontact 3'! would be out of electrical engagement with its terminal 34to open the starting circuit.

The movable member 35 of the switch has a dish shaped end portion 50representing a frustoconical, tapered surface 51, the dish-shaped endbeing centrally apertured as at 52 to permit the shaft 25 of the motorto extend therethrough.

As previously stated, movable contact carrying member 35 of the switchis actuated and controlled by a centrifugal member driven by the shaft25. This centrifugal member consists of a central pin or standard 60,one end of which is drivingly connected with the shaft 25, the other endhaving an enlarged head portion 6! providing an abutment for one end ofthe spring 62, the opposite end of the spring engaging a weight member63 slidable on the pin or standard 63. Theweight member 63 has adisclike element 64 of any suitable fabric, such as felt or the like,larger in diameter than any adjacent portion of the weight member 63 andengageable with the outer surface of the dish-shaped portion 50 of themovable contact member 35 of the switch. When the centrifugal member isinactive and the spring 62 maintains the weight member in normalposition adjacent thev driving shaft 25 the felt portion 64 of theweight member 63 engages the dished portion 50 of the switch member 35to hold it in the position as shown in Fig. 1 in which the contact 31engages terminal 34 and acts as the initial pivot for movement of theswitch member 35, contact 36 being held out of engagement with itscooperating stationary terminal 33 and the spring 46 compressed. Thus inthis inactive position the starting and running windings of the motorare interconnected so that when electrical energy is connected therewiththese windings will become active to start the electric motor.

It has been stated previously that the switch illustrated in the presentinvention is the one disclosed in the United States Patent 2,182,977,issued to Calvin J. Werner on December 12, 1939. In this patented switchthe pin or standard supporting the centrifugal weights is secured to thedriving shaft by extending through a hole in said shaft. In the patentedconstruction the center of the weights supporting pin or standard is notshiftable longitudinally of the shaft but on the contrary is fixedlengthwise of the shaft. This type of construction is disadvantageous,especially where the electric motor is commercially produced in largenumbers. By securing the weight supporting pin on the shaft in themanner as shown in the Werner patent the shaft 25 of the motor must beexactly located longitudinally in the motor so that the required spacingbetween the axis of the standard or pin 60 is redeterminedly spacedrelatively to the switch carried on the end cover 22. If, under highcommercial production, the stator 23 and consequently rotor 24 and shaft25 were pressed into the motor housing 23 too far the predeterminedspacing between the pin or standard 65 relative to the switch would notobtain, this pin 60 being too close to the switch in this instance, thuscausing the felt portion 64 of the weight member 63 to pinch the movablecontact member 35 of the switch and therefore seriously affect itsoperation as well as increasing the wear between the felt washer or disc64 and the dish portion 5|] of the switch upon which said felt washer 64rides continually in a circular path during the operation of the motor.If on the other hand the shaft 25 of the motor were not positionedinwardly of the frame sufiiciently then too great a spacing between thepin or standard 60 and the switch would obtain thereby materiallyaffecting the operation of the switch by the centrifugal member. Thus,it may be seen that to maintain the highest efiiciency of switchoperation and to reduce wear to aminimum the predetermined spacingbetween the centrifugal weight supporting pin or standard 60 and theswitch itself must be maintained, a difiicult and expensiverequirevment, particularly where electric motors are produced in greatnumbers commercially.

The present invention provides means for drivingly attaching thecentrifugal element to the shaft while maintaining the predeterminedspacing between the pin or standard 60 and the" switch regardless of thevariations in the position of the stator 23, rotor 24 and its shaft 25in the motor housing. In'Fig. 1, the end cover 22 has a central cupshaped member 10 rigidly secured thereto coaxial of the housing andsubstantially of the shaft 25 of the motor. The inner end of this cup isrecessed to. receive a spacing element or washer II, the exposed endsurface of said Washer H being predeterminedly spaced relatively to theswitch and its component parts, particularly the movable contact member35 and its associated stationary contact terminals 32 and 33. Thisspacin collar H provides an abutment for the end of a sleeve member 72slidably fitting upon the shaft 25. Fig. 2 shows the inner end of theshaft 25, which extends into the sleeve 12, as beit must rotate withsaid shaft but, due to the elongated slot 73, relative lengthwisemovement between the shaft and its surrounding sleeve 12, may obtain. Asprin 76 is interposed between the end of the shaft 25 and an abutmentformed within the sleeve 12, this spring substantially urging the sleeve12 to engage and ride upon the spacing collar H. The holes in the sleeve12 through which the weight supporting pin or standard 60 extends aredefinitely located relatively to the end of the sleeve 12 engageablewith the spacing collar H. Thus, the axis of the pin or standard 60 ispredeterminedly spaced and held in said predetermined space by thespacing collar ll. Therefore, if the motor parts 23, 24 and 25 are movedinto the housing 20 beyond the proper location therein the shaft 25merely slides within sleeve 12 and in no way effects thepredesupporting-post or standard 60 and the switch.

If, on the contrary, parts 23, 24'and25 are notpushed into the housin asufiicient distance then shaft will not extend into the sleeve 12thesame-amount. However,- said sleeve 12 will still be maintainedagainst-the spacing collar 1| by the spring 16 and thus thepredetermined spacing between the switch and the post or standard of thecentrifugal element is maintained. If at any time it is necessary tovary this predetermined spacing, the spacing washer 1I may be replacedwith a thicker or a thinner one, dependent upon the'necessary or desiredspacing between the centrifugal element and-the switch.

Fig. 5 is a modified construction slightly different from the oneillustrated in Fig. 1. In theconstruction in Fig. 5 the end cover plateI22 of the motor has a ball bearing I23 in which the shaft I25 isrotatably journaled. The sleeve I12 is secured to shaft I25 by a screwI12 threaded in the sleeve and extending into a keyway I14 in the shaftI 25,-Whereby said sleeve is secured to the shaft so that it must rotatetherewith but may movelongitudinally thereon, The weight member I63 ofthe centrifugal element is slidably carried on the pin or standard I60which is rigidly secured to sleeve I12 in any suitable manner andextends radially therefrom. In assembling this construction, proper shimwashers I24 are placed about the shaft I25, said shim washers engage theinner race of the ball bearing I23 and beingin turn engaged by the oneend of the sleeve I12. The proper thickness of shims I24 will thereforepredeterminedly space the axis of the post or standard I60 of thecentrifugal device relatively to the switch and its elements and 3D. Aspring I16 is interposed between the sleeve I12 and the rotor body I24on shaft I25, this spring constantly urgingthe sleeve I12 intoengagement with the spacing shim washers I24 so as to maintain theproper spacing between the centrifugal element and the switch. Thus, theposition of the shaft and its rotor may vary axially without effectingthe predetermined spacin between the centrifugal element and the switch.If this spacing is to be altered different shim washers I24 are appliedso as to provide the proper spacing.

In Fig. 4 a further modification of the construction is illustrated.Here the sleeve 212, slidable on shaft 225, has the pin or standard 260extending through aligned holes therein and through the slotted end 213of the shaft 225. This pin is secured to sleeve 212 a predetermineddistance from its end engageable with spacing shim washers 21I fittedabout the shaft 225 and engaging the rotor body 224 secured to the shaft225. The sleeve 212 is held against these spacing shim washers 21I by anend thrust washer 220 engaged by a screw 221 threaded into the end ofthe shaft 225. Thus the proper selection of spacin shim washers 21I willmaintain the centrifugal element in desired spaced relation with theswitch supported on the end housing 222.

From the aforegoing it may be seen that the present invention providesan improvement for centrifugally actuated switches, particularly of thetype shown in the Werner patent supra, this improvement being of asimple nature and eliminating the expensive and time requiring necessityof absolute location of the rotating parts of the motor relatively tothe electric switch on the motor adapted to be actuated by the mechanismcarried and rotated by said rotating portions of the motor. Variations,if necessary, may easily be provided for by the mere changing of 6 thespacing washers, certain ones being standard for certain requiredspacing between centrifugal elements and the switch and others beingnecessary for variations in other spacings.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. In a device of the character described, a stationary housing; arotatable shaft; a control device attached to the housing said controldevice having a shiftable member; of centrifugal means driven by saidshaft and engaging said shiftable member, said means being operative inresponse to centrifugal force to actuate said shiftable member; a sleeveslidably carried by the shaft; means fixedly attaching the centrifugalactuating means to the sleeve and connecting the sleeve to the shaft forcausing the sleeve to rotate with the shaft and be slidablelongituciinally relatively thereto; an immovable locating spacerpresenting a surface predeterminately located relatively to the controldevice, said surface being engaged by one end of the sleeve; and meansengaging the other end of the sleeve for holding it against the spacer.

2. A locating device for a centrifugal switch actuated by a rotatingshaft, said switch comprising stationary contacts supported upon astationary frame, cooperating movable contacts carried by a springloaded actuator, and a spring loaded weight slidable on a rod driven bysaid shaft said weight engaging the actuator to control it; a spacerbearing carried by said stationary frame in predetermined relation tosaid stationary contacts thereon; a sleeve slidably mounted upon saidshaft and having the rod extending diametrically through it and througha slot in said shaft, rotatably securing said sleeve to said shaft; anda spring interposed between said shaft and sleeve and urging the latteragainst the spacer bearing for predeterminately locating the rodrelatively to the stationary contacts.

3. A locating device for a centrifugal switch in which a spring loadedcentrifugal member is driven by a rotating shaft and engages a springloaded contact carrier for controlling its operation in accordance withthe rotating speed of said shaft; a stationary frame supporting terminalcontacts of the switch; a predeterminately sized spacing member on saidframe; and a sleeve slidable on said shaft and operatively connected tosaid shaft to rotate therewith, said sleeve having said centrifugalmember attached thereto and being yieldably urged against said spacingmember for predeterminately locating said centrifugal member relativelyto the contact carrier regardless of the longitudinal location of saiddriving shaft.

4. In a device for predeterminately locating a centrifugal switchactuator carried and driven by a rotating shaft, relatively to theactuated member of the switch which is carried by a stationary housingin which the shaft is journalled, the combination with a sleeve on saidshaft secured thereto so as to be rotated therewith and capable oflongitudinal movement relatively thereto; said sleeve having saidcentrifugal switch actuator, fixed thereto so as to rotate therewith andbe spaced predeterminately from said one end of the sleeve; spacer meanson the housing, providing an abutment surface predeterminately locatedrelatively to said actuated member of the switch; and a spring engaging7 said sleeve and urgingitssaid one end into engagement with said spacermeans.

5. In a device of the character described, the combination with astationary housing in which a rotatable shaft is journalled, of acontrol ,device secured within said housing said device having ashiftable member spring actuated into its one position; a spring loadedcentrifugal actuator driven by said shaft and engaging said shiftablemember for controlling its operation; a sleeve slidably fitting uponsaid shaft; a pin secured to said sleeve and extending through alongitudinal slot in said shaft for securing said sleeve to said shaftto permit relative longitudinal movement therebetween and cause saidsleeve to-rotate with said shaft, said pin supporting said centrifugalactuator; and means for securing said sleeve upon said shaft so thatsaid centrifugal actuator is predeterminately located relatively to saidshiftable member.

6. In combination with a housing having a cover and a rotatable memberjournalled therein, of a switch secured to the cover and having amovable contact arm; a spring loaded centrifugal element engaging saidmovable contact arm for actuating it, said element being driven by saidrotatable member; a sleeve slidably carried by said rotatable member andyieldably urged to engage said cover; and means secured to said sleeveat a predetermined distance from its portion engaging said cover, saidmeans connecting said sleeve with said rotatable member to-permitsliding movement thereof relatively to said sleeve but causing saidsleeve to be rotated with said member, said means supporting saidcentrifugal element.

7. In combination with a housing having a cover and a rotatable memberjournalled therein, of a switch secured to the cover and having amovable contact arm; a spring loaded centrifugal element engaging saidmovable contact arm for actuating it, said element being driven by saidrotatable member; supporting means for said centrifugal element, adaptedto be placed on said rotatable member so as to be driven thereby yet to.be slidable longitudinally thereof; and means operative predeterminatelyto locate said supporting means on said rotatable member and secure itthereto whereby said centrifugal member is predeterminately locatedrelatively to said movable contact arm of the switch.

8. In combination with a housing having an attachable cover and a shaftrotating in said housing, of a switch consisting of stationary contactsinsulatingly attached to said cover and cooperating, shiftable contactsattached to a lever movably carried by said cover; a spacer disc in thecover, said disc having an exposed surface predeterminately locatedrelatively to said switch REFERENCES CITED The following references areof record in the file of this patent:

UNITED STATES PATENTS Name Date Diehl July 21, 1936 Number

